After some embarrassing hacking this week of two major corporate user accounts, Burger King and Jeep, Twitter is reminding its 500 million users worldwide to be more careful about their passwords.

"Your password should be at least 10 characters that include upper and lower case characters, numbers, and symbols," the social media giant warned in a blog post Tuesday. "You should always use a unique password for each Web site you use; that way, if one account gets compromised, the rest are safe."

More Factors Needed

A top cyber-security expert told us the hacks might have been prevented if Twitter introduced a two-factor authentication, or 2FA, for log-ins. A 2FA system combines a password with another obstacle, such as a security question or an image that the user must recognize.

"I imagine security-conscious brands would leap at the chance to have that extra layer of protection," said cyber-security expert Graham Cluley of Sophos International.

Cluley said that, after resetting passwords on some 250,000 possibly compromised accounts earlier this month, Twitter has put a help-wanted ad on the Jobs section of its home page seeking experts in product security specializing in 2FA.

"But the main problem is that too many people use easy-to-crack passwords, or re-use passwords on multiple sites," Cluley said. "The Burger King and Jeep hacks were essentially mischievous rather than malicious, but imagine if a popular brand with millions of followers was hacked and tweeted out a link to a malware-laden Web site instead.

"The brand's followers would not be impressed, and would potentially lose data and perhaps money as a result."

Other fairly routine advice offered by the Twitter blog response to what the social media giant termed only as "a fair amount of conversation about account security on Twitter" includes watching out for suspicious links, making sure you are not logging in to your account on a third-party site and (duh) not giving out your password or user name to third parties, "especially those promising to get you followers or make you money."

It's unlikely any of those amateurish moves were made by officials of Burger King or Jeep when they were hacked this week.

Followers of Burger King may have been shocked to find out that the fast-food chain was "sold to McDonald's." The hacker even switched the Burger King profile picture to a McDonald's logo.

In Jeep's case, one phony tweet announced that Jeep, a division of Chrysler Group LLC, was "sold to Cadillac" and there were taunts that the company's name stood for "Just Empty Every Pocket."

Other nasty tweets followed on both accounts until access was restored to rightful owners. Some had the hashtag #OPMadcow while others had @DFNCTSC, which stands for Defonic Team Screen Name Club, a hacker group.

A Bright Side

In Burger King's case, at least, the news isn't all bad: The number of followers went up from 83,000 to 110,000 within an hour, Slashgear reported.

After regaining control, Burger King tweeted: "@Jeep Glad everything is back to normal," to which the car company responded: "@BurgerKing Thanks BK. Let us know if you want to grab a burger and swap stories -- we'll drive."